The Umayyad dynasty (Arabic: بَنُو أُمَيَّةَ, romanized: Banū Umayya, lit. 'Sons of Umayya'), or the Umayyads (Arabic: الأمويون, romanized: al-Umawiyyūn) was an Arab clan within the Quraysh tribe who were the ruling family of the Umayyad Caliphate in 661–750 and the Emirate and later Caliphate of Córdoba in 756–1031.

In the pre-Islamic period, the Umayyads were a prominent clan of the Meccan tribe of Quraysh, descended from Umayya ibn Abd Shams. Despite staunch opposition to the Islamic prophet Muhammad, the Umayyads embraced Islam before the former's death in 632. Uthman ibn Affan, an early companion of Muhammad from the Umayyad clan, was the third Rashidun caliph, ruling in 644–656, while other members held various governorships. This included Mu'awiya ibn Abi Sufyan, the long-time governor of Greater Syria, who opposed the fourth Rashidun caliph Ali ibn Abi Talib in the First Muslim Civil War (656–661) and afterwards founded the Umayyad Caliphate with its capital in Damascus. This marked the beginning of the Umayyad dynasty, the first hereditary dynasty in the history of Islam, and the only one to rule over the entire Islamic world of its time. Umayyad authority was challenged in the Second Muslim Civil War, during which the Sufyanid line of Mu'awiya (which includes only the three first Umayyad caliphs) was replaced in 684 by Marwan I, who founded the Marwanid line of Umayyad caliphs, which restored the dynasty's rule over the Caliphate and remained so until the fall of the Caliphate of Córdoba.

The Islamic empire reached its largest geographical extent under the Umayyads. The Umayyads drove on the early Muslim conquests, conquering the Maghreb, Hispania, Central Asia, Sind, and parts of Chinese Turkestan, but the constant warfare exhausted the state's military resources, while Alid and Kharijite revolts and tribal rivalries weakened the state from within. Finally, in 750 the Abbasids overthrew Caliph Marwan II and massacred most of the family. One of the survivors, Abd al-Rahman, a grandson of Caliph Hisham ibn Abd al-Malik, escaped to Muslim Spain, where he founded the Emirate of Córdoba, which his descendant, Abd al-Rahman III, transformed into a caliphate in 929. Under the Umayyads, al-Andalus became a centre of science, medicine, philosophy and invention during the Islamic Golden Age. The Caliphate of Córdoba disintegrated into several independent taifa kingdoms in 1031, thus marking the political end of the Umayyad dynasty.

The Umayyads, or Banu Umayya, were a clan of the larger Quraysh tribe, which dominated Mecca in the pre-Islamic era. The Quraysh derived prestige among the Arab tribes through their protection and maintenance of the Kaʿba, which at the time was regarded by the largely polytheistic Arabs across the Arabian Peninsula as their most sacred sanctuary. A Qurayshite leader, Abd Manaf ibn Qusayy, who based on his place in the genealogical tradition would have lived in the late 5th century, was charged with the maintenance and protection of the Kaʿba and its pilgrims. These roles passed to his sons Abd Shams, Hashim and others. Abd Shams was the father of Umayya, the eponymous progenitor of the Umayyads.

Umayya succeeded Abd Shams as the qa'id (wartime commander) of the Meccans. This position was likely an occasional political post whose holder oversaw the direction of Mecca's military affairs in times of war, instead of an actual field command. This early experience in military leadership proved instructive, as later Umayyads would be known and recognized for possessing considerable political and military organizational capabilities. The historian Giorgio Levi Della Vida suggests that information in the early Arabic sources about Umayya, as with all the ancient progenitors of the tribes of Arabia, "be accepted with caution", but "that too great skepticism with regard to tradition would be as ill-advised as absolute faith in its statements". Della Vida asserts that since the Umayyads who appear at the beginning of Islamic history in the early 7th century were no later than third-generation descendants of Umayya, the latter's existence is highly plausible.

By circa 600, the Quraysh had developed trans-Arabian trade networks, organizing caravans to Syria in the north and Yemen in the south. The Banu Umayya and the Banu Makhzum, another prominent Qurayshite clan, dominated these trade networks. To secure these routes, they developed economic and military alliances with the nomadic Arab tribes that controlled the northern and central Arabian desert expanses, gaining them a degree of political power in Arabia.

Muhammad was a member of the Banu Hashim, a Qurayshite clan related to the Banu Umayya through their shared ancestor, Abd Manaf. When he began his religious teachings in Mecca, he was opposed by most of the Quraysh. He found support from the inhabitants of Medina and relocated there with his followers in 622. The descendants of Abd Shams, including the Umayyads, were among the principal leaders of Qurayshite opposition to Muhammad. They superseded the Banu Makhzum, led by Abu Jahl, as a result of the heavy losses that the Banu Makhzum's leadership incurred fighting the Muslims at the Battle of Badr in 624. An Umayyad chief, Abu Sufyan, thereafter became the leader of the Meccan army that fought the Muslims under Muhammad at the battles of Uhud and the Trench.

Abu Sufyan and his sons, along with most of the Umayyads, embraced Islam toward the end of Muhammad's life, following the Muslim conquest of Mecca. To secure the loyalty of prominent Umayyad leaders, including Abu Sufyan, Muhammad offered them gifts and positions of importance in the nascent Muslim state. He installed another Umayyad, Attab ibn Asid ibn Abi al-Is, as the first governor of Mecca. Although Mecca retained its paramountcy as a religious center, Medina continued to serve as the political center of the Muslims. Abu Sufyan and the Banu Umayya relocated to the city to maintain their growing political influence.